Inertia type air cleaning device



1952 J. H. CRANKSHAW ET AL 2,615,519

INERTIA TYPE AIR CLEANING DEVICE Filed Jan. 28, 1949 gQiE lrwvehtors. John H. Crarwkshavv,

William S.()' Kelly Theif y Patented Nov. 4, 1952 UNITED STATES PAT OF F ICE INERTIA TYPERAIR CLEANING DEV-ICE John H; Crankshaw and Williams. ()Kelly, Erie;

Pa., assignors to General"Electriclcompanypa corporation ofiNew York Application January. '28, 1949, SeriaTNo; 73,254

(Cl. 183-75i) 2 la'ims. 1:

Our invention relates to' devices" for removing dirt particles from the atmosphere or'other gaseous" medium, and more particularly to dirt removing devices of the inertia type: It is the general object of our invention to provide an improved inertia type device for removing from a gas impurities in solid or liquid form having greater" density than the gas.

Itis *wellk'nownthat the airof the atmosphere containsvarying amounts of dirt'and' dust. It also is generally-known that machines of many types; particularly electrical machines, require thecirculationof air'over or' through them to provide adequate ventilation. When itis necessary'to pass air through theinterior of a' machine through. ducts or other" air" passages, the

It' isan object offour" invention to provide a simple...and reliable. device which removes a large percentage. of the dirt and other foreign material. including water from atmospheric air to.

makesuch air. suitable foruse in the ventilation of machinessuch .asthose described above.

Incarryingout our invention in one form, we provide anenclosed. electric-motor with a shaft extensionon one end- On this shaft extension isamountedan axialflow fan arranged to draw airover. the. motor enclosing. cover. from the 0ppositeend of the motor. The portion of the enclosure which. covers the opposite. end' of the motor is conical'in form and provides a deflecting. surface for the air andunseparated dirt therein. Surroundingthe motor-with a radial space between them is. an outer casing. which. provides aseconddeflecting surface. Between theouter casing and themotor isa barrier which separates radially that portion of' the intervening space nearest the fan into an inner clean air passage and an outer dirtyair passage. The single fan provides a pressure difierential in both passages. A plurality ofstationary' air turning vanes pro je'cvthrough said barrier; connecting said outer vention, reference should behadto the accom-- panying drawing, Fig. 1 of which is a partially cut-away sectional view of one embodiment thereof; while- Fig. 2 is a schematic diagram illustrating the manner in which inertia separation of the dirt from the air is accomplished.

Referring-to Fig. lot the drawing; an electric motor driven axial flow blower embodying the air cleaning device of our invention is illustrated generally by thenumeral I. The apparatus i comprises an electric motor having an outer cylindrically shaped stator frame member 2 enclosing stator coils 3 and the laminated stator core p'ortion l. Inside the stator is located a rotor comprising squirrel cage winding 5- and laminated rotor core portion 6 mounted on a shaft 7. The shaft 'l'is supported at one end by ball bearings 8 and atthe other by similar ball bearings (not shown). A tubular member 9 provides means for lubricating ball bearings 8 and a similar tubular member It provides for the lubrication of the ball bearings at the opposite end of the motor;

Stator member 2 of the electricmotor is securely fastened to a supporting circular base member H. Member H hasa plurality of equally spaced-air'turning vanes l2 securely fastened to the outerperiphery thereof. The outer extremities of turningvanes [2 are secured to an outer'flanged supporting member l3 which in turn" issecurely bolted to a solid frame member M- by a plurality of bolts 15 through spacer members t6. The electric motoris thus supported by turning vanes l2 through'members I3 and E6.

The electric motor has a single shaft extension (not'shown) on which is mounted an'axial flowfancomprisinga hub member H and a plurality of equally spaced blades it. The axial flow fan ll, [8 draws air and dirt longitudinally over'the surface of the electric motor from the end opposite the fan in the direction indicated by. the arrows.

Atthe inlet end-of thegapparatus, the motor is equipped withan'enc'losing: or end shield member 19 which has an outwardly projecting conical surface sharply to deflect the air and dirt as they enter the combined blower and cleaning apparatus I. Surrounding the electric motor with a radial space between them is an'outer casing 20: Between outer 'casing2ll and stator member 2 of the electric motor is an intermediate member or barrier 2| radially separating a portion of the space between casing 20 and motor frame 2 into an outer dirt passage B and an inner clean air passage C. Intermediate member 2| extends also through the space between members II and I3 through and around turning vanes l2 in order to form two separate passages to fan l1, l8. At the discharge side of fan H, H! are located openings 22 and 23 in members l6 and I4, respectively, to provide for the discharge of dirt outside the cleaning apparatus.

In the operation of the motor driven blower incorporating our invention, the rotation of fan l1, l8 creates a pressure differential which causes atmospheric air and dirt contained therein to be drawn into apparatus at the annular opening A. The mixture of air and dirt impinges on the surface of member I9 and is deflected radially toward outer casing 26. Both air and dirt must then change direction a second time in order to continue through the apparatus but the dirt, because of its greater mass, does not change direction as readily as the air. Therefore, a large percentage of the dirt falls into space B between members 20 and 2|. A small percentage of the air also enters space B, and the dirt and this small percentage of air are drawn through space B by fan I'l, H3 and discharged to the atmosphere through openings 22 and 23. The cleaned air enters space C between members 2 and 2| and is discharged by fan I'l, I8 into a clean air duct D on the discharge side of the fan.

A ring 24 at the inlet end of the apparatus may be used for lifting purposes but is not essential to the operation of the apparatus.

It is readily apparent that the inertia separation of dirt from air in a machine embodying our invention is accomplished by the motion of dirt particles in planes which coincide with the longitudinal axis of the machine. In other Words, the fan I8 in Fig. 1 is not an essential element of our invention, nor are the turning vanes l2 and the rotating motion of the air produced thereby. This is illustrated more clearly by Fig. 2 on the accompanying drawing.

Our invention is illustrated schematically in Fig. 2 with the dirt and air mixture entering at A in a direction substantially parallel to the center line and impinging on parabolically shaped surfaces E, which deflect both air and dirt radially. The outer casing adjacent opening B deflects them again and restores approximately the original direction of flow. The dirt and a small percentage of air pass into opening B and on to zone F, while the clean air passes into the opening C and continues on to zone D. In order to cause the device to operate in accordance with our invention, it is only necessary that there be a pressure differential between points A and F and points A and D, and these pressure differentials may be provided in any desired manner, such as by a separate fan, blower, aspirator, or other means.

We have found that by the use of our invention it is possible readily to remove 80 per cent or more by weight of foreign material in atmospheric air, the exact percentage depending upon the density of the foreign material. An important feature of the invention is that it is self-cleaning, inasmuch as the dirt and foreign material are discharged back to the atmosphere along with a small percentage of the air that was drawn into the machine. By adjusting the location of member 2| longitudinally, thereby affecting the cooperative relation of the leading edge of member 2| and the air deflecting portion of the outer casing, it is possible selectively to vary the size and density of particles which are removed from the air. It is also possible by radial variation of the location of member 2| selectively to vary the quantity of particles which are removed.

The mixture of dirt and air may be passed through one device embodying our invention and the air from the clean air passage of this first device then immediately passed through another similar device. In this manner, by the use of two deflecting surfaces in series, each deflecting surface having a pair of radial clean air and dirt passages associated with it, the percentage of dirt and foreign material removed from the air is greatly increased.

While we have illustrated and described particular embodiments of our invention, many modifications will occur to those skilled in the art. Therefore, it should be understood that we intend to cover by the appended claims any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An apparatus for removing dirt from the atmosphere comprising an elongated outer casing of varied diameter circular cross section, means providing for the flow of dirty air to be cleaned into one end of said outer casing in a direction substantially parallel to the center line of said casing, a completely enclosed elongated center member coaxially positioned on the center line of said outer casing, means for sharply deflecting said dirty air radially toward said casing, said means comprising an outwardly disposed conical projection on the dirty air inlet end of said center member, an intermediate coaxially positioned barrier separating a portion of the radial space between said outer casing and said center member into an outer longitudinal dirty air passage and an inner longitudinal clean air passage, said outer casing deflecting said dirty air again whereby it resumes flow in a direction substantially parallel to said center line, the leading edge of said barrier being positioned adjacent the portion of said outer casing which deflects said dirty air the second time in cooperative relation therewith whereby a substantial portion of the dirt in the incoming air passes into said outer passage because of the relatively greater density thereof while a major portion of the clean air passes into said inner passage because of its relatively lesser density, the motion of the dirt particles during and between said deflections occurring in planes substantially coinciding with said center line, a plurality of radially disposed air turning vanes supporting said center member inside said outer casing, an electric motor positioned inside said enclosed center member, and an axial flow fan driven by said electric motor.

2. A combined air blower and dirt separating apparatus comprising a completely enclosed electric motor having a shaft extension on one end, an axial flow fan positioned on said shaft extension for drawing dirty air to be cleaned over the enclosure of said motor from the end opposite said shaft extension end, the direction of flow of said air being approximately parallel to the axis of said motor shaft, means for deflecting said dirty air radially outwardly from the axis of said motor, said means comprising an outwardly projecting conically shaped surface on the end of said motor opposite said shaft extension end, an outer casing of circular cross section around said motor in coaxial radially spaced relation therewith, said outer casing deflecting said dirty air again whereby it resumes substantially its original direction of flow, a plurality of radially positioned air turning vanes connecting said motor and said outer casing and supporting said motor inside said casing, and an intermediate barrier member coaxially positioned between said motor and said outer casing separating a portion of the space between said motor and said outer casing into an inner clean air passage and an outer dirty air passage, the leading edge of said barrier being positioned adjacent the portion of said outer casing which provides the second deflecting surface in cooperative relation therewith whereby a large part of the dirt in the incoming air together with a small portion of the incoming air pass into said dirty air passage and the balance of both dirt and air pass into said clean air passage.

JOHN H. CRANKSHAW. WILLIAM S. OKELLY.

REFERENCES CITED The following references are of record in the file of this patent:

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